In recent years, mobile phones including camera modules account for the majority of types of mobile phones. Since such a camera module has to be housed in a mobile phone, there has been a demand for a camera module that is smaller and lighter than digital cameras.
Further, there is an increasing number of cases where a camera module that provides an automatic focusing (AF) function by means of a lens drive device is mounted in an electronic device such as a mobile phone. There are various types of lens drive devices including a type utilizing a stepping motor, a type utilizing a piezoelectric element, and a type utilizing a VCM (Voice Coil Motor). Such lens drive devices are currently commercially available.
On the other hand, in such a situation that the camera module having the automatic focusing function has become common, an image stabilizing function has been attracting rising attention as a next featuring function of a camera module. The image stabilizing function has been widely used in digital cameras and movies, whereas the image stabilizing function has rarely been used in mobile phones. This is because there are problems such as a size issue for employing the image stabilizing function in mobile phones. However, proposals for a novel structure of an image stabilizing mechanism that can be downsized are currently arising. Accordingly, it is predictable that camera modules for mobile phones having an image stabilizing function increase in the future.
Patent Literature 1 describes a “barrel shift” image stabilizing device as an image stabilizing mechanism. The image stabilizing device described in Patent Literature 1 is an image stabilizing device arranged to correct camera shake, by moving an entire automatic focusing lens drive device or a movable section thereof in a first direction and a second direction which are orthogonal to an optical axis and that are orthogonal to each other and thereby moving a lens barrel along the optical axis, the image stabilizing device including a focus coil and a permanent magnet which is disposed on an outer side of the focus coil in a radical direction of the focus coil with respect to the optical axis while facing the focus coil. The image stabilizing device includes (i) a base disposed apart from a bottom surface of the automatic focusing lens drive device, (ii) a plurality of suspension wires each of which has one end fixed to an outer periphery of the base, extends along the optical axis, and supports the entire automatic focusing lens drive device or the movable section thereof in such a manner that the entire automatic focusing lens drive device or the movable section thereof can rock in the first direction and the second direction, and (iii) a camera shake correcting coil disposed to face the permanent magnet.
Patent Literature 2 describes a technique for improving impact resistance of an image stabilizing device in which suspension wires as described in Patent Literature 1 are used. Patent Literature 2 describes a lens drive device including (i) a first supporting body that holds a lens and is capable of moving in a direction of an optical axis of the lens, (ii) a second supporting body that holds the first supporting body in such a manner that the first supporting body can move in the direction of the optical axis, (iii) a fixed body that holds the second supporting body in such a manner that the second supporting body can move in directions that are substantially orthogonal to the direction of the optical axis, (iv) a first drive mechanism for driving the first supporting body in the direction of the optical axis, (v) a second drive mechanism for driving the second supporting body in a predetermined first direction substantially orthogonal to the direction of the optical axis, (vi) a third drive mechanism for driving the second supporting body in a second direction substantially orthogonal to the direction of the optical axis and to the first direction, (vii) a plurality of wires for connecting the second supporting body and the fixed body, and (viii) a buckling prevention member for preventing buckling of the plurality of wires. The wires are formed linearly. The second supporting body is supported by the fixed body by means of the wires in such a manner that the second supporting body can move in the directions substantially orthogonal to the optical axis. The buckling prevention member is made of an elastic material and is elastically deformed in the direction of the optical axis by a force smaller than the buckling load on the wires.